Data transmission systems have gained worldwide popularity due to their broad applications in different environments, such as shopping malls or business buildings. Such systems may present a meaningful and efficient solution to transmit data and distribute information (e.g., traffic information, weather information, or advertisements) to a plurality of users who may be interested in the information. Advances in computers, communications, and wireless networks further increase development of these data transmission systems.
For example, a conventional data transmission system may be a broadcasting system. The broadcasting system may include a remote server and multiple broadcasting devices (e.g., panel computers or television set-top boxes) in different locations. Each of the multiple broadcasting devices may have a media device (e.g., a display or a speaker). The remote server stores and manages information to be broadcasted. The multiple broadcasting devices receive the information from the remote server through wired or wireless networks, and then broadcast the information to a plurality of users with their media devices.
FIG. 1 shows a broadcasting system 100 as an example of a conventional data transmission system. The system 100 includes a remote server 102 located in a data center and multiple broadcasting devices 104-1,104-2, . . . , 104-K (K is the total number of the broadcasting devices) in different locations. For example, the broadcasting device 104-1 may be a panel computer in a shopping mall and show new arrivals of products; the broadcasting device 104-2 may be a television set-top box in a grocery store and provide product discount information; the broadcasting device 104-3 may be another panel computer in a business building and display news items, etc. All information on the broadcasting devices 104-1, 104-2, . . . , 104-K is received from the remote server 102 through wired or wireless networks, such as cables, Internet, or a wireless local-area network (WLAN).
Such conventional data transmission systems as the broadcasting system 100 are usually one-way, or push, systems, which pre-select data or information to be transmitted to the broadcasting devices. Users of the conventional data transmission systems may be unable to request specific data from the systems. In addition, for the broadcasting system 100, users who view or hear information from one of the broadcasting devices 104-1, 104-2, . . . , 104-K may still forget the information after they leave that one of the broadcasting devices 104-1, 104-2, . . . , 104-K, since the broadcasting devices 104-1, 104-2, . . . , 104-K may be in fixed positions.
With recent advances in mobile communication technologies (e.g., Bluetooth technology), mobile devices (e.g., cellular phones, Personal Digital Assistants (PDAs), or laptop computers) have begun to play an important role in data transmission systems. Data transmission systems with mobile devices may comprise at least one information processing unit (IPU) (e.g., a ticket vending machine having a wireless communication component) and at least one mobile device. The mobile device may wirelessly receive data from the IPU. For example, the mobile device may wirelessly receive electronic coupons from the ticket vending machine.
Compared to conventional data transmission systems like the broadcasting system 100, data transmission systems with mobile devices may enable users to request specific information from IPUs. However, signal coverage and bandwidth of an IPU are usually limited. For example, a mobile device may wirelessly receive data from an IPU within a range of 10 meter from the IPU. If a user of the mobile device leaves the signal coverage area of the IPU before the mobile device completely receives the data, the mobile device may be unable to receive the remaining data from the IPU.